JP7107319B2 - Light source device and projection display device - Google Patents

Description

The present disclosure relates to a light source device having a phosphor wheel and a projection display device having the same.

In recent years, the mainstream of solid-state light sources for projectors is to excite a Ce-YAG (cerium: yttrium, aluminum, garnet) phosphor and obtain red light and green light by cutting unnecessary wavelengths from the fluorescence emission using a filter. It has become. However, the color gamut of this method is as narrow as about 60% of the BT2020 standard. Also, when displaying with D65, which is the white point of the sRGB standard, the red light component of the fluorescence is rate-determining. As a result, about 30% of the green light component of fluorescence emission is discarded, resulting in a problem of reduced light source efficiency.

On the other hand, for example, Patent Literature 1 discloses a light source device with a wide emission wavelength range. In this light source device, excitation light is incident from the side of the Ce-YAG phosphor, and the red phosphor is placed behind the Ce-YAG phosphor, thereby suppressing the luminance saturation of the red phosphor and proposing a bright light source with a wide color gamut. .

JP 2012-114040 A

By the way, a light source for a projector is required to achieve both a wide color gamut and high brightness.

It is desirable to provide a light source device and a projection display device capable of achieving both a wide color gamut and high brightness.

A first light source device according to an embodiment of the present disclosure includes a light source section and a wavelength conversion element that emits fluorescence when excited by excitation light from the light source section, and the wavelength conversion element rotates about a rotation axis. a phosphor layer containing a plurality of phosphor particles; and a quantum dot layer containing a plurality of quantum dots, wherein the phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section. A spacer is arranged around the quantum dot layer, and the substrate and the phosphor layer are bonded via the spacer. A second light source device according to an embodiment of the present disclosure includes a light source section and a wavelength conversion element that emits fluorescence when excited by excitation light from the light source section, and the wavelength conversion element rotates about a rotation axis. a substrate, a phosphor layer containing a plurality of phosphor particles, and a quantum dot layer containing a plurality of quantum dots, and excitation light is provided between the phosphor layer and the quantum dot layer. A reflective dichroic membrane is arranged. A third light source device according to an embodiment of the present disclosure includes a light source section and a wavelength conversion element that emits fluorescence when excited by excitation light from the light source section, and the wavelength conversion element rotates about a rotation axis. a substrate, a phosphor layer containing a plurality of phosphor particles, and a quantum dot layer containing a plurality of quantum dots filled in a space formed in a binder layer, wherein the phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section.

A first projection display device according to an embodiment of the present disclosure includes a light source device having a wavelength conversion element, a light modulation element that modulates light emitted from the light source device, and a projection that projects the light from the light modulation element. and an optical system. The light source device mounted on this projection display device has the same components as the first light source device of the embodiment of the present disclosure. A second projection display device according to an embodiment of the present disclosure includes a light source device having a wavelength conversion element, a light modulation element that modulates light emitted from the light source device, and a projection that projects the light from the light modulation element. and an optical system. The light source device mounted on this projection display device has the same components as the second light source device of the embodiment of the present disclosure. A third projection display device according to an embodiment of the present disclosure includes a light source device having a wavelength conversion element, a light modulation element that modulates light emitted from the light source device, and a projection that projects the light from the light modulation element. and an optical system. The light source device mounted on this projection display device has the same components as the third light source device of the embodiment of the present disclosure.

In the first to third light source devices of one embodiment and the first to third projection display devices of one embodiment of the present disclosure, a plurality of and a quantum dot layer containing a plurality of quantum dots are arranged in this order with respect to the light source section. As a result, the excitation light first enters the phosphor layer. As a result, the quantum dot layer is excited mainly by fluorescence emission, thereby reducing the Stokes loss and suppressing the temperature rise of the quantum dot layer. Therefore, it is possible to reduce the change in emission output and the change in emission wavelength.

According to the first to third light source devices of one embodiment of the present disclosure and the first to third projection display devices of one embodiment, the phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section. As a result, the excitation light emitted from the light source is first incident on the phosphor layer, thereby reducing the Stokes loss, suppressing the temperature rise of the quantum dot layer, and increasing the light emission output of the quantum dot. Variations and changes in emission wavelength are reduced. Therefore, it is possible to increase the luminance and expand the color gamut of the light emitted from the wavelength conversion element.

Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

1 is a cross-sectional schematic diagram showing an example of a configuration of a phosphor wheel according to a first embodiment of the present disclosure; FIG. 2 is a schematic plan view of the entire phosphor wheel shown in FIG. 1. FIG. 2 is a schematic cross-sectional view of the entire phosphor wheel shown in FIG. 1. FIG. It is a sectional view showing composition of a quantum dot. FIG. 4 is a characteristic diagram showing the relationship between the distance between the phosphor layer and the quantum dot layer and the brightness of the projected image; FIG. 4 is a cross-sectional schematic diagram showing another example of the configuration of the phosphor wheel according to the first embodiment of the present disclosure; FIG. 2 is a flow chart explaining a manufacturing process of the phosphor wheel shown in FIG. 1; FIG. 2 is a schematic diagram showing a configuration example of a light source device having the phosphor wheel shown in FIG. 1; FIG. 9 is a schematic diagram showing a configuration example of a projector including the light source device shown in FIG. 8. FIG. FIG. 3 is a spectral diagram of light emitted from a phosphor wheel having only a phosphor layer provided on a substrate; 2 is a spectrum diagram of light emitted from a phosphor wheel having the configuration shown in FIG. 1; FIG. 9 is a characteristic diagram showing the spectrum of light emitted from a general light source device and the spectrum of light emitted from the light source device shown in FIG. 8; FIG. FIG. 5 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 1 of the present disclosure; FIG. 10 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 2 of the present disclosure; FIG. 11 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 3 of the present disclosure; FIG. 11 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 4 of the present disclosure; FIG. 11 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 5 of the present disclosure; FIG. 11 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 6 of the present disclosure; 18B is a schematic diagram showing a planar structure of a substrate that constitutes the phosphor wheel shown in FIG. 18A. FIG. FIG. 11 is a cross-sectional schematic diagram showing the configuration of a phosphor wheel according to Modification 7 of the present disclosure; FIG. 12 is a schematic cross-sectional view showing the configuration of a phosphor wheel according to Modification 8 of the present disclosure; FIG. 5 is a schematic cross-sectional view showing an example of a configuration of a phosphor wheel according to a second embodiment of the present disclosure; FIG. 7 is a cross-sectional schematic diagram showing another example of the configuration of the phosphor wheel according to the second embodiment of the present disclosure; FIG. 20 is a schematic plan view showing an example of the overall configuration of a phosphor wheel according to Modification 9 of the present disclosure; 24 is a schematic cross-sectional view showing an example of the configuration of the phosphor wheel shown in FIG. 23; FIG. FIG. 20 is a schematic plan view showing another example of the overall configuration of the phosphor wheel according to Modification 9 of the present disclosure; FIG. 20 is a schematic cross-sectional view showing the configuration of a fixed wavelength conversion unit according to Modification 10 of the present disclosure; FIG. 11 is a schematic diagram showing a configuration of a light source device having a fixed wavelength conversion section according to Modification 11 of the present disclosure; FIG. 21 is a schematic diagram illustrating a configuration example of a light source device according to modification 12 of the present disclosure;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. In addition, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The order of explanation is as follows.
1. First Embodiment (Light Source Device with Phosphor Wheel Having Phosphor Layer and Quantum Dot Layer on Substrate)
1-1. Configuration of Phosphor Wheel 1-2. Configuration of light source device 1-3. Configuration of Projector 1-4. Action and effect 2. Modification 2-1. Modification 1 (an example in which a quantum dot layer is sandwiched between a substrate and a phosphor layer and a binder layer is provided around the quantum dot layer)
2-2. Modification 2 (an example in which the quantum dot layer is sealed in the binder layer)
2-3. Modification 3 (example in which spacers are provided around the quantum dot layer)
2-4. Modification 4 (an example in which a spacer is provided around the quantum dot layer and sealed with a binder layer)
2-5. Modification 5 (an example in which the quantum dot layer is formed in the space formed by the substrate, the phosphor layer, and the gas barrier material)
2-6. Modified example 6 (an example in which the quantum dot layer has a micro-reflector structure)
2-7. Modification 7 (example in which a particulate phosphor layer is provided between the quantum dot layer and the counter substrate)
2-8. Modification 8 (example of fixing a particulate phosphor layer on the quantum dot layer)
3. Second Embodiment (Example of Transmissive Phosphor Wheel)
4. Modification 4-1. Modification 9 (example of time division phosphor wheel)
4-2. Modification 10 (example of fixed wavelength conversion element)
4-3. Modification 11 (Example of light source device having a fixed wavelength conversion element)
4-4. Modification 12 (an example of another configuration of the light source device)

<1. First Embodiment>
FIG. 1 schematically illustrates an example of a cross-sectional configuration of a wavelength conversion element (phosphor wheel 1) according to the first embodiment of the present disclosure. FIG. 2 schematically shows the overall planar structure of the phosphor wheel 1 shown in FIG. 1, and FIG. 1 shows the cross-sectional structure taken along line II shown in FIG. . FIG. 3 schematically shows the overall cross-sectional structure of the phosphor wheel 1 along line II-II shown in FIG. The phosphor wheel 1 constitutes, for example, a light source device (light source device 100) of a projection display device (projector 10) described later (see FIGS. 8 and 9). Phosphor wheel 1 of the present embodiment has quantum dot layer 13 disposed between substrate 11 and phosphor layer 12 provided on surface S1 side of substrate 11 .

(1-1. Configuration of Phosphor Wheel)
Phosphor wheel 1 of the present embodiment includes quantum dot layer 13 provided between substrate 11 and phosphor layer 12 provided on substrate 11 rotatable about a rotation axis (eg, axis 16J). configuration. The quantum dot layer 13 is sealed by a binder layer 14 between the substrate 11 and the phosphor layer 12, for example. The phosphor layer 12, the quantum dot layer 13, and the binder layer 14 are provided on the light incident surface (surface S1) side of the substrate 11, and are arranged in this order with respect to the light source section 110, which will be described later. A gas barrier material 15 is provided on the side surfaces of the phosphor layer 12 , the quantum dot layer 13 and the binder layer 14 .

The substrate 11 is for supporting the phosphor layer 12 and the quantum dot layer 13, and has, for example, a disk shape. Moreover, the substrate 11 preferably has a function as a heat dissipation member, and is made of an inorganic material such as a metal material or a ceramic material that has a high thermal conductivity and can be mirror-finished. Materials constituting the substrate 11 include, for example, aluminum (Al), copper (Cu), molybdenum (Mo), tungsten (W), cobalt (Co), chromium (Cr), platinum (Pt), tantalum (Ta), Single metals such as lithium (Li), zirconium (Zr), ruthenium (Ru), rhodium (Rh) or palladium (Pd), or alloys containing one or more of these. Alternatively, alloys such as CuW with a W content of 80 atomic % or more and CuMo with a Mo content of 40 atomic % or more can be used as the metal material forming the substrate 11 . Ceramic materials include, for example, silicon carbide (SiC), aluminum nitride (AlN), beryllium oxide (BeO), a composite material of Si and SiC, or a composite material of SiC and Al (where the SiC content is 50% above). The substrate 11 is rotatable in the direction of an arrow C by a motor 16, for example, with a normal line passing through the center of the substrate 11 as a rotation axis O. As shown in FIG.

The phosphor layer 12 contains a plurality of phosphor particles, is preferably formed in a plate shape, and is made of, for example, a so-called ceramic phosphor. The phosphor layer 12 is formed, for example, in an annular shape on the substrate 11 . The phosphor particles are particulate phosphors that absorb the excitation light EL1 emitted from the light source unit 110 and emit fluorescence FL1. As the phosphor particles, for example, fluorescence that emits yellow fluorescence (light in a wavelength range between the red wavelength range and the green wavelength range) when excited by a blue laser beam having a wavelength in the blue wavelength range (eg, 400 nm to 470 nm). substances are used. Examples of such fluorescent materials include YAG (yttrium-aluminum-garnet) materials. The average particle size of the phosphor particles is, for example, 5 μm or more and 40 μm or less, and the thickness of the phosphor layer 12 is preferably formed to be, for example, 40 μm or more and 200 μm or less.

The quantum dot layer 13 includes a plurality of quantum dots 13A. FIG. 4 shows the cross-sectional configuration of the quantum dot 13A. The quantum dots 13A are generally particles having a particle size of several nanometers. It is composed of a shell layer 13b and a coat layer 13c covering the shell layer 13b. The shell layer 13b is made of, for example, a semiconductor having a larger bandgap than the compound semiconductor forming the core portion 13a. _The coat layer 13c is intended to prevent a decrease in emission intensity due to aggregation or oxidation of the quantum dots 13A (specifically, the core portion 13a). ) or an aluminum oxide film (Al ₂ O ₃ film). The coat layer 13c has a thickness of 1 nm or more, for example.

The binder layer 14 seals the quantum dot layer 13 and bonds the substrate 11 and the phosphor layer 12 together. The binder layer 14 preferably has, for example, light transmittance (in particular, visible light transmittance) and light resistance. Furthermore, the binder layer 14 preferably has gas barrier properties. Examples of the constituent material of the binder layer 14 include silicon resin, epoxy resin, low-melting glass such as water glass, silicon oxide (SiO ₂ ), and aluminum oxide (Al ₂ O ₃ ).

The quantum dot layer 13 of the present embodiment may have, for example, a structure in which the space formed in the binder layer 14 is densely filled with the quantum dots 13A shown in FIG. A distributed configuration may also be used. Moreover, it is preferable that the distance between the phosphor layer 12 and the quantum dot layer 13 is as short as possible. FIG. 5 shows the relationship between the distance between the phosphor layer 12 and the quantum dot layer 13 and the brightness of the projected image. As the distance between the phosphor layer 12 and the quantum dot layer 13 is shorter, the efficiency of the optical system until the light emitted from the phosphor layer 12 and the quantum dot layer 13 is illuminated to a spatial modulation element such as an LCD, LCOS, or DMD, which will be described later. can be improved. Further, the quantum dot layer 13 may be configured to contain particles that scatter light, such as titanium oxide (TiO ₂ ). Light emission from the quantum dots 13</b>A can be efficiently extracted from the quantum dot layer 13 by including particles that scatter light.

The gas barrier material 15 is for suppressing penetration of oxygen and moisture into the quantum dot layer 13 , and is provided from the substrate 11 to the end surface of the phosphor layer 12 , for example. Examples of constituent materials of the gas barrier material 15 include single-layer films of SiO ₂ , SiN, AL ₂ O ₃ and ALO, and composite films in which two or more of the above materials are combined. The gas barrier material 15 may be omitted if the binder layer 14 has sufficient gas barrier properties.

The motor 16 is for rotating the phosphor wheel 1 at a predetermined number of revolutions. The motor 16 drives the phosphor wheel 1 so that the phosphor layer 12 and the quantum dot layer 13 rotate in a plane perpendicular to the irradiation direction of the excitation light EL emitted from the light source section 110, which will be described later. As a result, the irradiation position of the excitation light EL on the phosphor wheel 1 temporally changes (moves) at a speed corresponding to the number of rotations in a plane orthogonal to the irradiation direction of the excitation light.

Moreover, the phosphor wheel 1 of the present embodiment may be provided with members other than those described above. FIG. 6 schematically shows another example of the cross-sectional configuration of the phosphor wheel 1 of this embodiment.

The phosphor wheel 1 preferably has a reflective layer 17 formed on the surface S1 side of the substrate 11, for example, as shown in FIG. The reflective layer 17 is formed of, for example, a dielectric multilayer film, a metal film containing a metal element such as aluminum (Al), silver (Ag), or titanium (Ti). The reflective layer 17 reflects the excitation light EL1 emitted from the light source unit 110 and the fluorescence FL1 and FL2 (see FIG. 8) converted in the phosphor layer 12 and the quantum dot layer 13, thereby increasing the luminous efficiency of the phosphor wheel 1. It works to elevate. In addition, when forming the reflective layer 17, the board|substrate 11 does not need to have light reflectivity. In that case, the substrate 11 can be made of crystal material such as Si alone, SiC, diamond, sapphire, quartz, or glass.

Further, the phosphor wheel 1 may be provided with an optical thin film 18 between the phosphor layer 12 and the quantum dot layer 13, for example, as shown in FIG. The optical thin film 18 preferably has a function of reducing reflection loss of light wavelength-converted by the quantum dot layer at the interface between the phosphor layer 12 and the quantum dot layer 13, for example. Alternatively, it preferably has a function of reflecting short wavelengths (for example, wavelengths of 350 nm or more and 480 nm or less, such as blue light), which makes it possible to reduce deterioration of the quantum dots 13A.

Furthermore, the phosphor wheel 1 may be provided with an optical thin film 19 on the surface of the phosphor layer 12, for example, as shown in FIG. The optical thin film 19 preferably has a function of reducing reflection loss of visible light (specifically, the excitation light EL emitted from the light source unit 110) at the interface between the surrounding air and the phosphor layer 12. Specifically, it is preferable to provide an antireflection film. Alternatively, it preferably has a function of reflecting a certain percentage of the excitation light EL. For example, it is preferable to apply a dichroic coat to the surface of the phosphor layer 12 .

The phosphor wheel 1 of this embodiment can be manufactured, for example, as follows. FIG. 7 shows the flow of the manufacturing process of the phosphor wheel 1. As shown in FIG.

First, the phosphor layer 12 is formed (step S101). When the phosphor layer 12 is composed of a ceramic phosphor, it is formed using, for example, the following method. First, phosphor powder is obtained by coprecipitation method, solid phase reaction method, gas phase reaction method of various gases and solids, etc., and then fired at an appropriate temperature to adjust particle size, composition, uniformity, internal defects, etc. do. The obtained phosphor powder is formed into a suitable shape by, for example, a rubber press, and then subjected to HIP treatment. Thereby, a ceramic phosphor (phosphor layer 12) is obtained. Subsequently, the quantum dot layer 13 is formed by coating on the phosphor layer 12 (step S102). Next, a silicon layer that becomes the binder layer 14 is applied onto the surface S1 of the substrate 11 (step S103). After that, the quantum dot layer 13 and the binder layer 14 are bonded together (step S104). Finally, the gas barrier material 15 is formed from the binder layer 14 to the phosphor layer 12 on the surface S1 of the substrate 11 (step S105). Thus, the phosphor wheel 1 is completed. In addition, in order to prevent deterioration of the quantum dots due to oxidation, it is preferable to carry out in an inert atmosphere.

(1-2. Configuration of light source device)
FIG. 8 is a schematic diagram showing the overall configuration of the light source device 100. As shown in FIG. The light source device 100 has a phosphor wheel 1 , a light source section 110 , a polarizing beam splitter (PBS) 112 , a quarter wave plate 113 and a condensing optical system 114 . The phosphor wheel 1 is, for example, a reflective wavelength conversion element, and is rotatably supported by a shaft J16. Each member constituting the light source device 100 includes, from the phosphor wheel 1 side, a condensing optical system 114, a quarter-wave plate 113, and a PBS 112 in this order. placed on the optical path. The light source unit 110 is arranged in a direction orthogonal to the optical path of the combined light Lw and at a position facing one light incident surface of the PBS 112 .

The light source unit 110 has a solid light emitting device that emits light of a predetermined wavelength. In the present embodiment, a semiconductor laser element that oscillates excitation light EL (for example, blue laser light with a wavelength of 445 nm or 455 nm) is used as the solid-state light emitting element, and the light source section 110 ~ linearly polarized light (S polarized light). of excitation light EL is emitted.

When the light source unit 110 is composed of semiconductor laser elements, the excitation light EL having a predetermined output may be obtained by using one semiconductor laser element. may be configured to obtain the excitation light EL of a predetermined output. Furthermore, the wavelength of the excitation light EL is not limited to the above values, and any wavelength within the wavelength band of light called blue light can be used.

The PBS 112 separates the excitation light EL incident from the light source section 110 and the combined light Lw incident from the phosphor wheel 1 . Specifically, the PBS 112 reflects the excitation light EL incident from the light source section 110 toward the quarter-wave plate 113 . Further, the PBS 112 transmits the combined light Lw incident from the phosphor wheel 1 through the condensing optical system 114 and the quarter-wave plate 113, and the transmitted combined light Lw enters the illumination optical system 200 (described later). is incident on

The quarter-wave plate 113 is a phase difference element that produces a phase difference of π/2 with respect to incident light. In the case of polarized light, circularly polarized light is converted into linearly polarized light. In the present embodiment, the linearly polarized excitation light EL emitted from the polarization beam splitter 112 is converted into circularly polarized excitation light EL by the quarter-wave plate 113 . The circularly polarized excitation light component contained in the combined light Lw emitted from the phosphor wheel 1 is converted into linearly polarized light by the quarter-wave plate 113 .

The condensing optical system 114 converges the excitation light EL emitted from the quarter-wave plate 113 to a predetermined spot diameter, and emits the condensed excitation light EL toward the phosphor wheel 1. . The condensing optical system 114 converts the combined light Lw emitted from the phosphor wheel 1 into parallel light and emits the parallel light toward the quarter-wave plate 113 . The condensing optical system 114 may be composed of, for example, one collimating lens, or may be configured to convert incident light into parallel light using a plurality of lenses.

The configuration of the optical member that separates the excitation light EL incident from the light source unit 110 and the combined light Lw emitted from the phosphor wheel 1 is not limited to the PBS 112, and the light separation operation described above is possible. Any optical member can be used as long as it is stretched in a configuration that In addition, a cooling fan may be provided in the light source device 100 in order to cool the heat generated in the phosphor layer 12 and the quantum dot layer 13 due to the irradiation of the excitation light EL.

(1-3. Configuration of projector)
Next, the projection display device (projector 10) of the present disclosure will be described. FIG. 9 is a schematic diagram showing the overall configuration of a projector 10 having the light source device 100 shown in FIG. 8 as a light source optical system. In the following description, a reflective 3-LCD type projector that modulates light using a reflective liquid crystal panel (LCD) will be described as an example. The phosphor wheel 1 can also be applied to a projector using a transmissive liquid crystal panel, a digital micro-mirror device (DMD), or the like instead of the reflective liquid crystal panel.

As shown in FIG. 9, the projector 10 includes, in order, the light source device 100 described above, an illumination optical system 200, an image forming section 300, and a projection optical system 400 (projection optical system).

The illumination optical system 200 includes, for example, a fly-eye lens 210 (210A, 210B), a polarization conversion element 220, a lens 230, dichroic mirrors 240A, 240B, reflecting mirrors 250A, 250B from a position near the light source device 100, It has lenses 260A and 260B, a dichroic mirror 270, and polarizing plates 280A to 280C.

The fly-eye lens 210 (210A, 210B) aims to homogenize the illuminance distribution of the white light from the light source device 100. FIG. The polarization conversion element 220 functions to align the polarization axes of incident light in a predetermined direction. For example, light other than P-polarized light is converted into P-polarized light. Lens 230 converges the light from polarization conversion element 220 toward dichroic mirrors 240A and 240B. The dichroic mirrors 240A and 240B selectively reflect light in a predetermined wavelength range and selectively transmit light in other wavelength ranges. For example, dichroic mirror 240A mainly reflects red light toward reflecting mirror 250A. Also, the dichroic mirror 240B mainly reflects blue light toward the reflecting mirror 250B. Therefore, mainly green light is transmitted through both dichroic mirrors 240A and 240B and travels to reflective polarizing plate 310C (described later) of image forming section 300. FIG. Reflecting mirror 250A reflects light (mainly red light) from dichroic mirror 240A toward lens 260A, and reflecting mirror 250B reflects light (mainly blue light) from dichroic mirror 240B toward lens 260B. do. The lens 260A transmits the light (mainly red light) from the reflecting mirror 250A and converges it onto the dichroic mirror 270. FIG. The lens 260B transmits the light (mainly blue light) from the reflecting mirror 250B and converges it onto the dichroic mirror 270. FIG. The dichroic mirror 270 selectively reflects green light and selectively transmits light in other wavelength ranges. Here, the red light component of the light from lens 260A is transmitted. If the light from lens 260A contains a green light component, the green light component is reflected toward polarizing plate 280C. Polarizing plates 280A-280C include polarizers having polarizing axes in predetermined directions. For example, when the light is converted into P-polarized light by the polarization conversion element 220, the polarizing plates 280A to 280C transmit P-polarized light and reflect S-polarized light.

The image forming section 300 has reflective polarizing plates 310A to 310C, reflective liquid crystal panels 320A to 320C (light modulation elements), and a dichroic prism 330. FIG.

The reflective polarizers 310A to 310C transmit light with the same polarization axis as the polarized light from the polarizers 280A to 280C (for example, P-polarized light), and transmit light with other polarization axes (S-polarized light). It is reflective. Specifically, the reflective polarizing plate 310A transmits the P-polarized red light from the polarizing plate 280A in the direction of the reflective liquid crystal panel 320A. The reflective polarizing plate 310B transmits the P-polarized blue light from the polarizing plate 280B toward the reflective liquid crystal panel 320B. The reflective polarizing plate 310C transmits the P-polarized green light from the polarizing plate 280C toward the reflective liquid crystal panel 320C. The P-polarized green light that has passed through both the dichroic mirrors 240A and 240B and entered the reflective polarizing plate 310C passes through the reflective polarizing plate 310C and enters the dichroic prism 330 as it is. Further, the reflective polarizing plate 310A reflects the S-polarized red light from the reflective liquid crystal panel 320A and makes it enter the dichroic prism 330 . The reflective polarizing plate 310 B reflects the S-polarized blue light from the reflective liquid crystal panel 320 B to enter the dichroic prism 330 . The reflective polarizing plate 310</b>C reflects the S-polarized green light from the reflective liquid crystal panel 320</b>C to enter the dichroic prism 330 .

The reflective liquid crystal panels 320A to 320C perform spatial modulation of red light, blue light, or green light, respectively.

The dichroic prism 330 synthesizes the incident red light, blue light, and green light and emits them toward the projection optical system 400 .

The projection optical system 400 has lenses L410 to L450 and a mirror M400. The projection optical system 400 magnifies the light emitted from the image forming section 300 and projects it onto the screen 460 or the like.

(Operation of light source device and projector)
Next, operations of the projector 10 including the light source device 100 will be described with reference to FIGS. 8 and 9. FIG.

First, the motor 16 is driven in the light source device 100 to rotate the phosphor wheel 1 . After that, excitation light EL is oscillated from the light source unit 110 toward the PBS. After being reflected by the PBS 112 , the excitation light EL is transmitted through the quarter-wave plate 113 and the condensing optical system 114 in this order to irradiate the phosphor wheel 1 .

In the phosphor wheel 1, part of the excitation light EL (blue light) is absorbed in the phosphor layer 12 and converted into light in a predetermined wavelength band (fluorescence FL1; yellow light). A portion of the fluorescence FL1 emitted in the phosphor layer 12 is diffused together with a portion of the excitation light EL not absorbed in the phosphor layer 12 and reflected toward the condensing optical system 114 side. The fluorescence FL2 and excitation light EL that are not reflected by the phosphor layer 12 toward the condensing optical system 114 are absorbed by the quantum dot layer 13 and converted into light in a predetermined wavelength band (fluorescence FL2; red light). That is, the phosphor wheel 1 of this embodiment emits light in a wavelength band (for example, 480 nm to 680 nm) including yellow light and red light. A part of the fluorescence FL2 emitted in the quantum dot layer 13 is diffused together with the fluorescence FL2 not absorbed in the quantum dot layer 13 and the excitation light EL, and reflected toward the condensing optical system 114 side. The fluorescence FL2, FL2 and the excitation light EL that are not reflected toward the condensing optical system 114 in the quantum dot layer 13 are reflected toward the condensing optical system 114 by the reflecting layer 17 when the substrate 11 and the reflective layer 17 are provided. be done.

In the case where the surface of the phosphor layer 12 is provided with, for example, an optical thin film 19 (for example, a dichroic coat) having a function of reflecting a certain percentage of the excitation light EL as described above, part of the excitation light EL is The optical thin film 19 reflects the light toward the condensing optical system 114 .

As a result, the fluorescence FL1, FL2 and a part of the excitation light EL are combined in the phosphor wheel 1 to generate white light, and this white light (combined light Lw) is emitted toward the condensing optical system 114. be done.

After that, the combined light Lw passes through the condensing optical system 114 , the quarter-wave plate 113 and the PBS 112 and enters the illumination optical system 200 .

Combined light Lw (white light) incident from the light source device 100 sequentially passes through the fly-eye lens 210 (210A, 210B), the polarization conversion element 220, and the lens 230, and then reaches the dichroic mirrors 240A, 240B. .

Red light is mainly reflected by dichroic mirror 240A, and this red light is sequentially transmitted through reflecting mirror 250A, lens 260A, dichroic mirror 270, polarizing plate 280A and reflective polarizing plate 310A, and reaches reflective liquid crystal panel 320A. This red light is spatially modulated by the reflective liquid crystal panel 320A and then reflected by the reflective polarizing plate 310A to enter the dichroic prism 330. FIG. When the light reflected by dichroic mirror 240A onto reflecting mirror 250A contains a green light component, the green light component is reflected by dichroic mirror 270 and sequentially transmitted through polarizing plate 280C and reflective polarizing plate 310C. , reaches the reflective liquid crystal panel 320C. Blue light is mainly reflected by the dichroic mirror 240B and enters the dichroic prism 330 through a similar process. The green light transmitted through dichroic mirrors 240A and 240B also enters dichroic prism 330 .

The red light, blue light, and green light incident on the dichroic prism 330 are combined and emitted toward the projection optical system 400 as image light. The projection optical system 400 magnifies the image light from the image forming section 300 and projects it onto the screen 460 or the like.

(1-4. Action and effect)
As described above, in recent years, solid-state light sources for projectors mainly employ a system in which a Ce-YAG phosphor is excited and unnecessary wavelengths are cut off from the fluorescence emission by a filter to obtain red light and green light. . However, the color gamut of this method is as narrow as about 60% of the BT2020 standard. Also, when displaying with D65, which is the white point of the sRGB standard, the red light component of the fluorescence is rate-determining. As a result, about 30% of the green light component of the fluorescence emission is discarded, resulting in a problem of reduced light source efficiency.

Therefore, a technique has been developed in which excitation light is incident from the Ce-YAG phosphor side, and a red phosphor is placed behind the Ce-YAG phosphor to increase the red light component and improve the brightness in a wide color gamut. However, the effect is not sufficient, and the luminance is only slightly improved under conditions of relatively low excitation light density. Therefore, it is presumed that under high light density conditions, the luminance saturation of the red phosphor further reduces the improvement in luminance.

By the way, a light source for a projector is required to have an expanded color gamut. Wavelength conversion materials for solid-state light sources include quantum dots in addition to phosphors. Quantum dots can have a peak wavelength at a wavelength with high spectral efficiency, and the emission wavelength width can also be narrowed to the extent that speckles do not occur. In addition, since quantum dots have a short fluorescence lifetime, they are less likely to cause luminance saturation, and they have excellent quantum efficiency. be able to. However, when quantum dots are used under conditions of high excitation light density, there is a problem that the light source lifetime is shortened due to deterioration. In addition, quantum dots have the problem that their emission wavelengths vary greatly depending on the intensity of excitation light and temperature, compared to general phosphors such as YAG phosphors and SCASN phosphors.

On the other hand, in the present embodiment, the phosphor layer 12 containing a plurality of phosphor particles is provided on the surface S1 of the substrate 11, which is the incident surface of the excitation light EL1 emitted from the light source unit 110, and the phosphor layer 12 A quantum dot layer 13 containing a plurality of quantum dots is provided between the layer 12 and the substrate 11 . As a result, the excitation light EL1 first enters the phosphor layer 12, and the quantum dot layer 13 uses the fluorescence FL1 converted by the phosphor layer 12 as excitation light. As a result, the Stokes loss can be reduced, so that the temperature rise of the quantum dot layer 13 can be suppressed and the change in emission wavelength can be reduced.

FIG. 10 is a spectral diagram when only the phosphor layer 12 is formed on the substrate 11, and FIG. 11 is a spectral diagram of the light emitted from the phosphor wheel 1. FIG. As shown in FIG. 11, in the phosphor wheel 1 of the present embodiment, fluorescence FL2 (red light) emitted from the quantum dot layer 13 is combined with fluorescence FL1 (yellow light) emitted from the phosphor layer 12. As compared with FIG. 10, the color gamut can be expanded.

As described above, in the light source device 100 of the present embodiment, the quantum dot layer 13 is arranged between the substrate 11 and the phosphor layer 12 provided on the substrate 11 of the phosphor wheel 1. The excitation light EL1 emitted from the portion 110 is first converted into fluorescence FL1 in the phosphor layer 12, part of which is absorbed by the quantum dot layer 13 and converted into fluorescence FL2. As a result, the temperature rise of the quantum dot layer 13 is suppressed, and changes in light emission output and light emission wavelength are reduced. Therefore, from the phosphor wheel 1, as shown in FIG. 11, it is possible to obtain light emission with a wide color gamut and little color change.

FIG. 12 shows the spectrum of light emitted from a general light source device and the spectrum of light emitted from the light source device 100 of this embodiment. The spectrum of light emitted from the light source device 100 of this embodiment is represented by a solid line, and the spectrum of light emitted from a general light source device is represented by a dotted line. Further, a general light source device includes a phosphor wheel having a phosphor layer formed on a substrate. As shown in FIG. 12, in the light source device 100 of the present embodiment, the red component is increased but the green component is decreased as compared with the general light source device. However, in a light source device using a general phosphor wheel, the green component is discarded in order to achieve color balance. Therefore, in the light source device of the present embodiment, it is possible to improve the luminance under wide color gamut conditions.

In projectors using quantum dots as a wavelength conversion material, including the projector 10 of the present embodiment, blue light with a high absorption rate, for example, light with a wavelength of 445 nm to 465 nm or light with a shorter wavelength is used as excitation light. However, light with a short wavelength as described above tends to degrade the organic molecules that form the ligand portion of the quantum dots. In addition, there is a possibility that the bonding state at the interface between the core portion and the shell layer in the quantum dot may change and the wavelength conversion efficiency may decrease. In contrast, in phosphor wheel 1 of the present embodiment, fluorescence FL1 converted in phosphor layer 12 is used as excitation light in quantum dot layer 13 . This makes it possible to improve the lifetime of the quantum dots 13A and the phosphor wheel 1 having them.

Furthermore, in this embodiment, since the quantum dot layer 13 is sealed with the binder layer 14 and the gas barrier material 15, deterioration of the quantum dots 13A due to oxygen and moisture can be reduced.

Next, a second embodiment and modified examples 1 to 11 will be described. Below, the same reference numerals are assigned to the same constituent elements as in the first embodiment, and the description thereof will be omitted as appropriate.

<2. Variation>
(2-1. Modification 1)
FIG. 13 schematically illustrates a cross-sectional configuration of a phosphor wheel 2A according to Modification 1 of the present disclosure. FIG. 13 corresponds to a cross section taken along line II shown in FIG. In the phosphor wheel 2A of this modified example, the upper and lower surfaces of the quantum dot layer 13 are sealed with the substrate 11 and the phosphor layer 12, and the side surfaces of the quantum dot layer 13 are sealed with the binder layer 14 and the gas barrier material 15. It is.

(2-2. Modification 2)
FIG. 14 schematically illustrates a cross-sectional configuration of a phosphor wheel 2B according to Modification 2 of the present disclosure. FIG. 14 corresponds to a cross section taken along line II shown in FIG. A phosphor wheel 2</b>B of this modified example has a quantum dot layer 13 provided in a binder layer 14 .

The phosphor wheel 1 shown in the first embodiment may be configured as described above, in addition to sealing the quantum dot layer 13 on the phosphor layer 12 side with the binder layer 14 . The phosphor wheels 2A and 2B in modified examples 1 and 2 have the same effect as the first embodiment.

(2-3. Modification 3)
FIG. 15 schematically illustrates a cross-sectional configuration of a phosphor wheel 2C according to Modification 3 of the present disclosure. FIG. 15 corresponds to a cross section taken along line II shown in FIG. The phosphor wheel 2C of this modification has spacers 21 arranged around the quantum dot layer 13. In this phosphor wheel 2C, the substrate 11 and the phosphor layer 12 are joined via the spacers 21. ing.

As described above, in this modification, the spacers 21 are arranged between the substrate 11 and the phosphor layer 12, so that the film thickness of the quantum dot layer 13 is made uniform. As a result, the amount of light emitted from the quantum dot layer 13 is uniformed under the trajectory of the phosphor wheel 2C irradiated with the excitation light, and it is possible to reduce the output change and color change of the light source according to the rotation cycle. . The spacer 21 preferably has gas barrier properties, and is composed of, for example, a single layer film of SiO ₂ , SiN, AL ₂ O ₃ and ALO, or a composite film in which two or more of the above materials are combined.

(2-4. Modification 4)
FIG. 16 schematically illustrates a cross-sectional configuration of a phosphor wheel 2D according to Modification 4 of the present disclosure. FIG. 16 corresponds to a cross section taken along line II shown in FIG. The phosphor wheel 2D of this modified example is a combination of the first embodiment and the third modified example. It is encapsulated by layer 14 . Further, the side surface of the binder layer 14 may be appropriately provided with a gas barrier material 15 extending from the substrate 11 to the side surface of the phosphor layer 12 .

As described above, in this modification, the film thickness of the quantum dot layer 13 is made uniform by using the spacer 21, and the circumference thereof is sealed by the binder layer 14 and the gas barrier material 15, so that uniform chromaticity can be obtained. Light source emission and long-term color change stability can be obtained.

(2-5. Modification 5)
FIG. 17 schematically illustrates a cross-sectional configuration of a phosphor wheel 2E according to Modification 5 of the present disclosure. FIG. 17 corresponds to a cross section taken along line II shown in FIG. In the phosphor wheel 2</b>E of this modified example, the space formed by the substrate 11 , the phosphor layer 12 and the gas barrier material 15 is filled with the quantum dots 13</b>A to form the quantum dot layer 13 . Thus, the quantum dot layer 13 does not necessarily need to be provided with the binder layer 14 or the spacer 21 around it.

(2-6. Modification 6)
FIG. 18A schematically illustrates a cross-sectional configuration of a phosphor wheel 2F according to Modification 6 of the present disclosure. This FIG. 18A corresponds to a cross section taken along line II shown in FIG. FIG. 18B schematically shows a part of the planar structure of the substrate 11 that constitutes the phosphor wheel 2F. A phosphor wheel 2</b>F of this modified example has a configuration in which a reflection structure X (micro-reflector structure) is formed on the surface (surface S<b>1 ) of the substrate 11 .

The reflecting structure X is composed of a dam portion 11X provided on the surface S1 of the substrate 11. As shown in FIG. The dam portion 11X has, for example, a tapered shape, and is formed so as to divide the quantum dot layer 13 provided between the substrate 11 and the phosphor layer 12 into a plurality of spaces. A reflective layer 17, for example, is preferably formed on the surface of the substrate 11 including the dam portion 11X. As in the first embodiment, the reflective layer 17 is formed of, for example, a dielectric multilayer film or a metal film containing a metal element such as aluminum (Al), silver (Ag), or titanium (Ti). It is Also, instead of the reflective layer 17, a light scattering layer may be provided on the surface of the substrate 11 including the dam portion 11X. The light scattering layer is made of, for example, a titanium oxide (TiO ₂ ) film or a barium sulfate (BaSO ₄ ) film. Also, the dam portion 11X itself may be formed using a light scattering material such as TiO ₂ or BaSO ₄ .

The dam portion 11X is preferably formed so that a plurality of spaces partitioned by the dam portion 11X have, for example, a honeycomb shape as shown in FIG. 18B. As a result, the proportion of the dam portion 11X within the plane of the quantum dot layer 13 is minimized, and fluorescence FL2 converted in the quantum dot layer 13 can be extracted with high efficiency. The interval (w) between the adjacent dam portions 11X is preferably, for example, 400 μm or less, and the height (f) of the dam portions 11X is preferably, for example, 200 μm or less.

Thus, in this modification, the surface (surface S1) of the substrate 11 is provided with the reflection structure X that partitions the quantum dot layer 13 provided between the substrate 11 and the phosphor layer 12 into a plurality of spaces. did.
Thereby, for example, the light emission (fluorescence FL2) of the quantum dots 13A in one space (cell) partitioned by the reflective structure X can be suppressed from spreading to another adjacent space. That is, it is possible to suppress diffusion of the light emission (fluorescence FL2) of the quantum dots 13A into the quantum dot layer 13. FIG. Thereby, the light emission in the quantum dot layer 13 can be low etendue light emission as a light source, and for example, the light extraction efficiency to the incident side of the fluorescence FL2 can be improved. Note that this light extraction efficiency is improved not only for the fluorescence FL2, but also for the fluorescence FL1 and the excitation light EL. Therefore, it is possible to improve the brightness of the projected image of the projector 10 .

(2-7. Modification 7)
FIG. 19 schematically illustrates a cross-sectional configuration of a phosphor wheel 2G according to Modification 7 of the present disclosure. FIG. 19 corresponds to a cross section taken along the line II shown in FIG. In the phosphor wheel 2G of this modified example, the phosphor layer 22 is formed using particulate phosphor. The phosphor layer 22 in this modified example is formed by, for example, providing a binder layer 14 having a quantum dot layer 13 inside, and filling phosphor particles between the binder layer 14 and the counter substrate 23. It is

The counter substrate 23 is made of a material having optical transparency, and has a property of transmitting the excitation light EL1 and the fluorescence FL1 and FL2 converted by the phosphor particles and quantum dots 13A. Examples of the constituent material of the opposing substrate 23 include quartz, glass, sapphire, and crystal. Among these, it is preferable to use sapphire, which has a high thermal conductivity. In addition, resin materials such as polyethylene terephthalate (PET) and silicone resin can be used when a low-output light source is used in the light source device 100 described later.

Although not shown in FIG. 19, it is preferable to seal the periphery of the phosphor layer 12 by providing, for example, a gas barrier material 15 from the substrate 11 to the end surface of the substrate 31 .

(2-8. Modification 8)
FIG. 20 schematically illustrates a cross-sectional configuration of a phosphor wheel 2H according to Modification 8 of the present disclosure. FIG. 20 corresponds to a cross section taken along line II shown in FIG. In the phosphor wheel 2H of this modified example, similar to the seventh modified example, the phosphor layer 22 is formed using particulate phosphors. The phosphor layer 22 in this modified example is composed of, for example, a particle accumulation layer formed by sintering phosphor particles.

As described above, even if the phosphor layer 22 has a structure other than the ceramic phosphor as in the first embodiment, the same effects as in the first embodiment can be obtained. In addition to the above, the phosphor layer 22 may be configured, for example, using resin or a binder together with a plurality of phosphor particles. The binder binds the adjacent phosphor particles and other phosphor particles, and also binds the phosphor particles and, for example, the surface of the binder layer 14 . The binder is desirably an inorganic binder, for example containing cross-linking values of inorganic materials such as water glass. Water glass is a silicic acid compound called sodium silicate, potassium silicate or sodium silicate, in which SiO ₂ (silicic anhydride) and Na ₂ O (sodium oxide) or K ₂ O (potassium oxide) It is a liquid mixed in proportions. Its molecular formula is Na ₂ O.nSiO ₂ . In addition, a binder such as TEOS (Si(OC ₂ H ₅ ) ₄ ), silicon resin, or epoxy resin may be used.

<3. Second Embodiment>
FIG. 21 schematically illustrates a cross-sectional configuration of a wavelength conversion element (phosphor wheel 3A) according to the second embodiment of the present disclosure. FIG. 21 corresponds to a cross section taken along line II shown in FIG. The phosphor wheel 3 of the present embodiment is a transmissive phosphor wheel, and the substrate 11 is made of a light-transmissive material.

In the phosphor wheel 3 of the present embodiment, the quantum dot layer 13 is arranged between the substrate 31 and the phosphor layer 12 in the same manner as in the first embodiment. The excitation light EL1 is first incident on the phosphor layer 12 . Further, in this embodiment, optical thin films 32 and 33 are provided on the phosphor layer 12 and between the phosphor layer 12 and the quantum dot layer 13, respectively.

The substrate 31 is made of, for example, a light-transmissive material like the counter substrate 23, and directs the excitation light EL1 and the fluorescence FL1 and FL2 converted in the phosphor layer 12 and the quantum dot layer 13 to the surface S2 side. It has the property of being permeable. Examples of constituent materials of the substrate 31 include quartz, glass, sapphire, and crystal. Among these, it is preferable to use sapphire, which has a high thermal conductivity. In addition, resin materials such as polyethylene terephthalate (PET) and silicone resin can be used when a low-output light source is used in the light source device 100 described later.

The optical thin film 32 transmits the excitation light EL<b>1 and reflects the fluorescence FL<b>1 converted by the phosphor layer 12 . By providing the optical thin film 32 on the phosphor layer 12, the fluorescence FL1 converted by the phosphor layer 12 can be efficiently extracted from the emission side (substrate 31 side).

The optical thin film 33 reflects the fluorescence FL2 converted by the quantum dot layer 13, and light having a shorter wavelength than the fluorescence FL2 (specifically, the excitation light EL1 and the fluorescence FL1 converted by the phosphor layer 12). is permeable. By providing the optical thin film 33 between the phosphor layer 12 and the quantum dot layer 13, the fluorescence FL2 converted by the quantum dot layer 13 can be efficiently extracted from the emission side (substrate 31 side).

Moreover, the phosphor wheel 3A of the present embodiment may be provided with members other than those described above. FIG. 22 schematically shows a cross-sectional configuration of a phosphor wheel 3B as another example of phosphor wheel 3A of the present embodiment.

The phosphor wheel 3B has a phosphor layer 12 and a quantum dot layer 13 provided on a surface S1 of a substrate 31 in this order. In the phosphor wheel 3B, the excitation light EL1 emitted from the light source section 110 passes through the substrate 31 and first enters the phosphor layer 12. As shown in FIG. In this phosphor wheel 13 B, an optical thin film 32 is provided between the substrate 31 and the phosphor layer 12 , and an optical thin film 33 is provided between the phosphor layer 12 and the quantum dot layer 13 . The phosphor wheel 3B is further provided with an optical thin film 34 on the quantum dot layer 13 (specifically, on the binder layer 14 sealing the quantum dot layer 13) and an optical thin film 35 on the surface S2 side of the substrate 31. It is

The optical thin film 34 is for reducing the reflection loss of the fluorescence FL1, FL2 at the interface between the binder layer 14 and the surrounding air. A similar effect can be obtained by providing a fine uneven structure on the surface of the binder layer 14 instead of the optical thin film 34 .

The optical thin film 35 serves to reduce the reflection loss of the excitation light EL1 at the interface between the surrounding air and the substrate 31. Specifically, it is preferable to provide an antireflection film.

As described above, in the phosphor wheels 3A and 3B of the present embodiment, a so-called transmissive phosphor wheel is configured by using the substrate 31 having optical transparency. With the above configuration, the same effects as those of the reflective phosphor wheel 1 described in the first embodiment can be obtained.

<4. Variation>
(4-1. Modification 9)
FIG. 23 schematically shows a planar configuration of a phosphor wheel 4A according to Modification 9 of the present disclosure. The phosphor wheel 4A of this modified example is a time-division phosphor wheel, and three regions corresponding to R, G, and B (a red conversion region 140R, a green conversion region 140R, and a 140G and a blue diffusion region 140B).

For example, as shown in FIG. 24, the red conversion region 140R includes a blue dichroic filter 42B, a phosphor layer 12, a red quantum dot layer 13R, a binder layer 14 and a red filter 43R arranged in this order on the surface S1 of the substrate 31. It has a laminated construction. The blue dichroic filter 42B transmits only blue light (excitation light EL1) and reflects light of other wavelengths. The red quantum dot layer 13R is excited by the fluorescence FL1 converted by the phosphor layer 12 to emit red fluorescence (FL2R). The red filter 43R transmits only red light (FL2R) and reflects light of other wavelengths. As a result, the red light FL2R is extracted together with the fluorescence FL1 from the red conversion region 140R.

Similar to the red conversion region 140R, the green conversion region 140G has a blue dichroic filter 42B, a phosphor layer 12, a green quantum dot layer 13G, a binder layer 14, and a green filter 43G laminated in this order on the surface S1 of the substrate 31. configuration. The green quantum dot layer 13G is excited by the fluorescence FL1 converted by the phosphor layer 12 to emit green fluorescence (FL2G). The green filter 43G transmits only green light (FL2G) and reflects light of other wavelengths. As a result, green light FL2G is extracted from green conversion region 140G. Note that the green quantum dot layer 13G may be omitted from the green conversion region 140G. By providing the green quantum dot layer 13G, the green component extracted from the green conversion region 140G is improved.

For example, a diffusion layer 41 is formed in the blue diffusion region 140B. The diffusion layer 41 diffuses the excitation light EL1 to make the diffusion of the blue light extracted from the blue diffusion region 140B uniform with the red light and green light extracted from other regions. In addition, a blue quantum dot layer and a binder layer 14 sealing it may be provided in the blue diffusion region 140B. By providing the blue quantum dot layer, it is possible to change the wavelength of the excitation light EL1, which is blue light, and reduce the occurrence of speckles.

Further, the phosphor wheel 4A of this modified example may be configured as shown in FIG. 25, for example. The phosphor wheel 4B shown in FIG. 25 is provided with areas corresponding to white (W; white conversion area 140W) in addition to R, G, and B. FIG. In the white conversion region 140W, for example, a blue dichroic filter 42B, a phosphor layer 12 and a diffusion layer 41 are laminated in this order on the surface S1 of the substrate 31. As shown in FIG. By providing the white conversion area 140W in addition to the red conversion area 140R, the green conversion area 140G, and the blue diffusion area 140B, it is possible to improve the luminance.

Although FIGS. 23, 24 and 25 show only layers having optical functions, the phosphor wheels 4A and 4B may include other members. For example, a sapphire layer or a glass layer may be provided in order to improve the flatness and heat dissipation of the substrate 31 .

Further, the phosphor wheels 3A and 3B of the second embodiment and the phosphor wheels 4A and 4B of the ninth modification can have the configurations of the first to sixth modifications, like the phosphor wheel 1. .

(4-2. Modification 10)
FIG. 26 schematically illustrates a cross-sectional configuration of a wavelength conversion element (fixed wavelength conversion section 5) according to Modification 10 of the present disclosure. The fixed wavelength conversion section 5 has condensing lenses 51A and 51B, a wavelength conversion layer 52, a heat sink 53, a heat spreader 54, and a lens holder 55. As shown in FIG.

In the fixed wavelength conversion unit 5, a condenser lens 51B and a condenser lens 51A are arranged in order of incidence of excitation light. The condenser lens 51A has a predetermined lens surface to which the wavelength conversion layer 52 is bonded. The condensing lens 51A converges the excitation light incident through the condensing lens 51B on the wavelength conversion layer 52 . Also, the condenser lens 51A emits the fluorescence component from the wavelength conversion layer 52 toward the condenser lens 51B.

The condenser lens 51B condenses the excitation light from the light source section 20 toward the condenser lens 51A. In addition, the condenser lens 51B condenses the fluorescence component from the wavelength conversion layer 52 incident through the condenser lens 51A toward the light source section 20. As shown in FIG. The condenser lens 51B has, for example, an outer diameter larger than that of the condenser lens 51A, and its outer peripheral portion is held by a lens holder 55. As shown in FIG.

The wavelength conversion layer 52 is, for example, a laminate of a phosphor layer and a quantum dot layer, and the phosphor layer is provided on the excitation light incident side as in the first embodiment. . It is preferable that all of the wavelength conversion layer 52 and the region other than the region where the wavelength conversion layer 52 is bonded on the predetermined lens surface of the condenser lens 51A are adhered to the heat dissipating member via the heat conductive layer.

The heat sink 53 and the heat spreader 54 function as heat radiation members that diffuse the heat generated by the wavelength conversion layer 52 and lower the temperature. Also, the heat spreader 54 has a function of lowering the temperature of the condensing lens 51A. The heat sink 53 is provided on the back surface of the heat spreader 54 . The heat sink 53 has a function of transferring the heat diffused by the heat spreader 54 to the air and dissipating the heat. The heat sink 53 and the heat spreader 54 are made of a material with relatively high thermal conductivity such as metal or ceramics. For example, it is made of copper, aluminum, sapphire, or molybdenum.

The lens holder 55 is for positioning and holding the condenser lens 51B. The lens holder 55 may be integrated with the heat spreader 54 .

(4-3. Modification 11)
FIG. 27 illustrates a schematic configuration of a light source device 500 including a wavelength conversion element (fixed wavelength conversion section 6) according to Modification 11 of the present disclosure. The fixed wavelength conversion section 6 includes a concave mirror 61, a wavelength conversion section 64, and a diffusion plate 65. Using the concave mirror 61, the wavelength of the excitation light EL emitted from the laser group 111 of the light source section 110 is converted. The structure is such that the light is focused on the portion 64 . The wavelength converting portion 64 is composed of, for example, a rod-shaped quantum dot layer 63 and a phosphor layer 62 provided on the surface of the quantum dot layer 63 . In the fixed wavelength conversion section 6 , the excitation light EL emitted from the light source section 110 is diffused inside the concave mirror 61 by the diffusion plate 65 . The diffused excitation light EL is reflected by the concave mirror 61 and focused on the wavelength conversion section 64 . The wavelength conversion unit 64 converts most of the excitation light EL into fluorescence FL1. The converted fluorescence FL1 is irradiated onto the quantum dot layer 13, a part thereof is converted into, for example, red fluorescence FL2, and emitted toward the lens 118 together with the fluorescence FL1.

As described above, the wavelength conversion element constituting the light source device of the present disclosure is the rotary wavelength conversion element (phosphor wheels 1, 2A .

(4-4. Modification 12)
FIG. 28 is a schematic diagram showing the overall configuration of a light source device 600 according to Modification 12 of the present disclosure. This light source device 600 is used, for example, as the light source device of the projector 10 shown in FIG.

Light source device 600 includes phosphor wheel 1 , diffuser plate 621 , light source section 610 that emits excitation light or laser light, lenses 612 to 615 , dichroic mirror 616 , and reflecting mirror 617 . The phosphor wheel 1 is, for example, a reflective wavelength conversion element, and is rotatably supported by a shaft J16. The diffuser plate 621 is rotatably supported by a shaft J621. The light source unit 610 has a first laser group 610A and a second laser group 610B. The first laser group 610A is a semiconductor laser element 611A that oscillates excitation light (for example, wavelength 445 nm or 455 nm), and the second laser group 610B is a semiconductor laser element 611B that oscillates blue laser light (for example, wavelength 465 nm). It is arranged in multiple numbers. For convenience, EL1 is the excitation light emitted from the first laser group 610A, and EL2 is the blue laser light emitted from the second laser group 610B (hereinafter simply referred to as blue light).

In this modification, the phosphor wheel 1 is configured such that the excitation light EL1 transmitted from the first laser group 610A through the lens 612, the dichroic mirror 616, and the lens 613 in order enters the phosphor layer 12 and the quantum dot layer 13 in this order. are arranged so that Fluorescence FL1 from the phosphor wheel 1 is reflected by the dichroic mirror 616 and then passes through the lens 614 to travel to the outside, ie, the illumination optical system 200. FIG. The diffusion plate 621 diffuses the blue light EL2 that has passed through the reflection mirror 617 from the second laser group 610B. The blue light EL2 diffused by the diffusion plate 621 passes through the lens 615 and the dichroic mirror 616, and then passes through the lens 614 to the outside, that is, the illumination optical system 200. FIG. A cooling fan may be provided in the light source device 600 in order to cool the heat generated in the phosphor layer 12 and the quantum dot layer 13 due to the irradiation of the excitation light EL1.

Next, the operation of projector 10 including light source device 600 will be described with reference to FIGS. 9 and 28. FIG.

First, in the light source device 600, the motors 16 and 622 are driven, and the phosphor wheel 1 and the diffusion plate 621 are rotated. After that, excitation light EL1 and blue light EL2 are oscillated from first laser group 610A and second laser group 610B in light source section 610, respectively.

The excitation light EL1 is oscillated from the first laser group 610A, passes through the lens 612, the dichroic mirror 616 and the lens 613 in order, and then irradiates the phosphor layer 12 of the phosphor wheel 1. FIG. The phosphor layer 12 absorbs part of the excitation light EL1, converts it into fluorescence FL1, which is yellow light, and emits it toward the lens 613. FIG. The quantum dot layer 13 absorbs a portion of the fluorescence FL1 converted by the phosphor layer 12, converts it into fluorescence FL2, for example, red light, and emits it toward the lens 613. FIG. After being reflected by the dichroic mirror 616 , the fluorescence FL 1 and FL 2 are transmitted through the lens 614 toward the illumination optical system 200 .

The blue light EL2 is oscillated from the second laser group 610B, passes through the reflecting mirror 617, and is then applied to the diffusion plate 621. FIG. The diffusion plate 621 diffuses the blue light EL2 and emits it toward the lens 615 . After passing through the dichroic mirror 616 , the blue light EL<b>2 passes through the lens 614 toward the illumination optical system 200 .

In this way, the light source device 600 causes the illumination optical system 200 to receive white light obtained by synthesizing the fluorescent light FL (FL1, FL2), which is yellow light and red light, and the blue light (EL2).

As described above, the present disclosure has been described with reference to the first and second embodiments and modifications 1 to 12, but the present disclosure is not limited to the above embodiments and the like, and various modifications are possible. . For example, the materials and thicknesses of the layers described in the above embodiments are merely examples, and the present invention is not limited to these, and other materials and thicknesses may be used.

Further, a device other than the projector may be configured as a projection display device according to the present technology. For example, in the above-described first embodiment, a reflective 3LCD type projector using a reflective liquid crystal panel as an optical modulation element has been described. It can also be applied to a so-called transmissive 3LCD type projector.

Furthermore, the light source device according to the present technology may be used in a device other than a projection display device. For example, the light source device 100 of the present disclosure may be used for illumination purposes, and is applicable to, for example, automobile headlamps and light sources for lighting up.

Note that the present technology can also have the following configuration.
(1)
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit ,
A spacer is arranged around the quantum dot layer,
The substrate and the phosphor layer are bonded via the spacer.
Light source device.
(2)
The light source device according to (1), wherein the wavelength conversion element has a first optical film on an incident side of the excitation light of the phosphor layer.
(3)
The light source device according to (2), wherein the first optical film is an antireflection film or a dichroic film that reflects a certain percentage of the excitation light.
(4)
The light source device according to any one of (1) to (3), wherein the wavelength conversion element has a second optical film between the phosphor layer and the quantum dot layer.
(5)
The light source device according to (4), wherein the second optical film is a dichroic film that reflects the excitation light.
(6)
The light source device according to any one of (1) to (5), wherein the wavelength conversion element has a third optical film between the substrate and the quantum dot layer.
(7)
The light source device according to (6), wherein the third optical film is a dielectric multilayer film or a light-reflective metal film.
(8)
(1) to (7), wherein the quantum dot layer is fixed on the phosphor layer by a binder having optical transparency, and the phosphor layer is bonded to the substrate via the binder; The light source device according to any one of .
(9)
The light source device according to any one of (1) to (8), wherein the quantum dot layer is covered with a light-transmitting binder on upper and lower surfaces.
(10)
The light source device according to any one of (1) to (9), wherein the end surface of the quantum dot layer is sealed with a gas barrier material.
(11)
The light source device according to any one of (1) to (10) , wherein the phosphor layer is made of a ceramic phosphor.
(12)
Any one of (1) to (11) above, wherein the phosphor layer is formed by filling a space between the light-transmissive substrate and the quantum dot layer with the plurality of phosphor particles. 1. The light source device according to claim 1.
(13)
The light source device according to any one of (1) to (12) , wherein the phosphor layer includes the plurality of phosphor particles bound together by a binder.
(14)
The light source device according to any one of (1) to (13) , wherein the phosphor layer is formed continuously in the rotation circumferential direction of the substrate.
(15)
The light source device according to any one of (1) to (14) , wherein the substrate is light reflective or light transmissive.
(16)
The light source device according to any one of (1) to (15), wherein the substrate has a plurality of regions emitting different wavelengths.
(17)
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit,
A dichroic film that reflects the excitation light is arranged between the phosphor layer and the quantum dot layer.
Light source device.
(18)
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
A quantum dot layer containing a plurality of quantum dots filled in the space formed in the binder layer,
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section
Light source device.
(19)
a light source device;
a light modulation element that modulates light emitted from the light source device;
a projection optical system for projecting light from the light modulation element,
The light source device
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit ,
A spacer is arranged around the quantum dot layer,
The substrate and the phosphor layer are bonded via the spacer.
Projection type display device.
(20)
a light source device;
a light modulation element that modulates light emitted from the light source device;
a projection optical system for projecting light from the light modulation element,
The light source device
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit,
A dichroic film that reflects the excitation light is arranged between the phosphor layer and the quantum dot layer.
Projection type display device.
(21)
a light source device;
a light modulation element that modulates light emitted from the light source device;
a projection optical system for projecting light from the light modulation element,
The light source device
a light source ;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
A quantum dot layer containing a plurality of quantum dots filled in the space formed in the binder layer,
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section
Projection type display device.

This application claims priority based on Japanese Patent Application No. 2017-157570 filed on August 17, 2017 at the Japan Patent Office, and the entire contents of this application are incorporated herein by reference. to refer to.

Depending on design requirements and other factors, those skilled in the art may conceive various modifications, combinations, subcombinations, and modifications that fall within the scope of the appended claims and their equivalents. It is understood that

Claims (21)

a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit ,
A spacer is arranged around the quantum dot layer,
The substrate and the phosphor layer are bonded via the spacer.
Light source device. 2. The light source device according to claim 1, wherein said wavelength conversion element has a first optical film on an incident side of said excitation light of said phosphor layer. 3. The light source device according to claim 2, wherein said first optical film is an antireflection film or a dichroic film that reflects a certain percentage of said excitation light. 2. The light source device according to claim 1, wherein said wavelength conversion element has a second optical film between said phosphor layer and said quantum dot layer. 5. The light source device according to claim 4, wherein said second optical film is a dichroic film that reflects said excitation light. 2. The light source device according to claim 1, wherein said wavelength conversion element has a third optical film between said substrate and said quantum dot layer. 7. The light source device according to claim 6, wherein said third optical film is a dielectric multilayer film or a metal film having light reflectivity. 2. The light source device according to claim 1, wherein said quantum dot layer is fixed on said phosphor layer by a binder having optical transparency, and said phosphor layer is bonded to said substrate via said binder. . 2. The light source device according to claim 1, wherein said quantum dot layer is covered with a light-transmissive binder on its upper and lower surfaces. 2. The light source device according to claim 1, wherein the end face of said quantum dot layer is sealed with a gas barrier material. 2. The light source device according to claim 1, wherein said phosphor layer is made of a ceramic phosphor. 2. The light source device according to claim 1, wherein said phosphor layer is formed by filling a space between said quantum dot layer and said light-transmitting substrate with said plurality of phosphor particles. 2. The light source device according to claim 1, wherein said phosphor layer comprises said plurality of phosphor particles bound together by a binder. 2. The light source device according to claim 1, wherein said phosphor layer is formed continuously in the rotation circumferential direction of said substrate. 2. The light source device according to claim 1, wherein said substrate is light reflective or light transmissive. 2. The light source device according to claim 1, wherein said substrate has a plurality of regions emitting different wavelengths. a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit,
A dichroic film that reflects the excitation light is arranged between the phosphor layer and the quantum dot layer.
Light source device. a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
A quantum dot layer containing a plurality of quantum dots filled in the space formed in the binder layer,
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section
Light source device. a light source device;
a light modulation element that modulates light emitted from the light source device;
a projection optical system for projecting light from the light modulation element,
The light source device
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit ,
A spacer is arranged around the quantum dot layer,
The substrate and the phosphor layer are bonded via the spacer.
Projection type display device. a light source device;
a light modulation element that modulates light emitted from the light source device;
a projection optical system for projecting light from the light modulation element,
The light source device
a light source;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
a quantum dot layer including a plurality of quantum dots;
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source unit,
A dichroic film that reflects the excitation light is arranged between the phosphor layer and the quantum dot layer.
Projection type display device. a light source device;
a light modulation element that modulates light emitted from the light source device;
a projection optical system for projecting light from the light modulation element,
The light source device
a light source ;
a wavelength conversion element that emits fluorescence when excited by the excitation light from the light source;
The wavelength conversion element is
a substrate rotatable about a rotation axis;
a phosphor layer containing a plurality of phosphor particles;
A quantum dot layer containing a plurality of quantum dots filled in the space formed in the binder layer,
The phosphor layer and the quantum dot layer are arranged in this order with respect to the light source section
Projection type display device.

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